Cytoplasmic and salt-extracted peroxidase and IAA oxidase activities were studied in Phaseolus vulgaris hypocotyls treated with gibberellic acid (GA, 200 µM), naphthyl acetic acid (NAA, 100 µM) and distilled water control (DW). Peroxidase activity was assayed with four hydrogen donors during the initial phase of hypocotyl elongation. Though peroxidase activity showed a decreasing trend with time in all the hydrogen donors studied; considerable variation with different hydrogen donors was observed. NAA had maximum peroxidase activity as compared to DW or GA treatment. The activity showed a clear inverse correlation with hypocotyl growth. IAA oxidase activity showed a similar trend with growth as peroxidase activity. A highly significant correlation was observed between peroxidase and IAA oxidase activities and high molecular weight xyloglucan content (P<0.001). Finally, the possible role of peroxidase and IAA oxidase activities in hypocotyl elongation growth is discussed.
The reaction of nitrite (NO-2) with horseradish peroxidase and lactoperoxidase was studied. Sequential mixing sopped-flow measeruments gave the following values for the rate constants of the reaction of nitrite with compounds II (oxoferryl heme intermediates) of horseradish peroxidase and lactoperoxidase at pH 7.0, 13.3 ± 0.07 mol-1dm3s-1 and 3.5 ± 0.05 · 104mol-1dm3s-1, respectively. Nitrite, at neutral pH, influenced measurements of activity of lactoperoxidase with typical substrates like 2,2'-azino-bis[ethyl-benzothiazoline-(6)-sulphonic acid] (ABTS), guaiacol or thiocyanate (SCN-). The rate of ABTS and guaiacol oxidation increased linearly with nitrite concentration up to 2.5-5 mmol dm-3. On the other hand, two-electron SCN- oxidation was inhibited in the presence od nitrite. Thus, nitrite competed with the investigated substrates of lactoperoxidase. The intermediate, most probably nitrogen dioxide (*NO2), reacted more rapidly with ABTS or guaiacol than did lactoperoxidase compound II. It did not, however, effectively oxidize SCN- to OSCN-. NO-2 did not influence the activity measurements of horseradish peroxidase by ABTS or guaiacol method.
Changes in peroxidases and glycosidases activities in cytoplasmic and ionically wall-bound fraction of developing seed of Hibiscus esculentum were studied. In both fractions, the activity of peroxiases assayed with ferulic acid and caffeic acid as a hydrogen donors, showed inverse correlation with the cell enlargement (sink size development phase). Activities of glycosidases, on the other hand, showed positive correlation with the sink development and sink filling period of the developing seed. The role of both the enzymes, glycosidases and peoxidase in seed development is discussed.
Effects of salt stress on the activity of peroxidase (PRX) isozyme and leaf proteins were studied in the three strawberry varieties, Camarosa, Tioga and Chandler. Plants were watered with modified 1/3 Hoagland nutrient solution containing 0 (control), 8.5, 17.0 and 34.0 mM NaCl for 30 days fallowing 20 days acclimation. PRX activity was assayed in leaf extracts and PRX profiles of control and salt treated plants were performed by native polyacrylamide gel electrophoresis (PAGE).During the salt stress Tioga and Camarosa tolerated the cellular damage with less electrolyte leakage while Chandler exhibited a severe cellular damage with the highest (87.5 % in 34.0 mM NaCl treatment) electrolyte leakage. Total soluble protein content was decreased by salinity in Tioga (from 11.35 to 5.86 mgg-1DW) and Chandler (from 9.35 to 3.90 mgg-1DW) while it was almost unchanged in Camarosa. Salt stress increased total and specific PRX activity as compared with the control in all the varieties. In native PAGE, one basic isoperoxidase band (Rf=0.27) was observed commonly with different band intentity in all the treatments. Therefore, it might be associated with lignification and recovery of cell membrane damage in strawberry plants under salt stress.
The genetic Variation of Reed Grass Calamagrostis arundinacea (L.) Roth was investigated in 25 populations in various geographic regions of Poland. A total of 907 individuals were sampled for electrophoretic analysis of peroxidase loci (11 allozymes). Populations were characterised by genetic parameters e.g. heterozygosity level, Wright's fixation index (F) and polymorphism coefficient (Pg). Mean values of interpopulation variability level (GST=0.0310), total genetic diversity (HT=0.4102) and gene flow between populations (Nm=7.805) were also examined. All the populations were polymorphic and they remain in Hardy Weinberg equilibrium.
Differences between 13 common reed (Phragmites australis) populations, growing in urban conditions within the town of Poznań (western Poland), are described by 8 morphological traits of panicles' variability and the frequency of peroxidase (dimeric and monomeric) allozymes. Values of morphological characters were processed statistically using agglomerative clustering by the closest neighbours (UPGMA) method based on Euclidean distances. Proteins were separated in the starch gel electrophoretic procedure, showing cathodic migration. Populations are polymorphic and have a certain level of heterozygosity. The level of populations' diversity (DST = 0.097) is lower than the intra-population variability (GST = 0.187). The gene flow between populations is rather low (Nm = 1.090).
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.